So someone leaked 2011 era PowerVR SGX microcode and user space... And now everyone is pissing themselves like a bunch of overexcited puppies...
I've been fed links from several sides now, and i cannot believe how short-sighted and irresponsible people are, including a few people who should know better.
STOP TELLING PEOPLE TO LOOK AT PROPRIETARY CODE.
Having gotten that out of the way, I am writing this blog to put everyone straight and stop the nonsense, and to calmly explain why this leak is not a good thing.
Before i go any further, IANAL, but i clearly do seem to tread much more carefully on these issues than most. As always, feel free to debunk what i write here in the comments, especially you actual lawyers, especially those lawyers in the .EU.
LIBV and the PVR.Let me just, once again, state my position towards the PowerVR.
I have worked on the Nokia N9, primarily on the SGX kernel side (which is of course GPLed), but i also touched both the microcode and userspace. So I have seen the code, worked with and i am very much burned on it. Unless IMG itself gives me permission to do so, i am not allowed to contribute to any open source driver for the PowerVR. I personally also include the RGX, and not just SGX, in that list, as i believe that some things do remain the same. The same is true for Rob Clark, who worked with PowerVR when at Texas Instruments.
This is, however, not why i try to keep people from REing the PowerVR.
The reason why i tell people to stay away is because of the design of the PowerVR and its driver stack: PVR is heavily microcode driven, and this microcode is loaded through the kernel from userspace. The microcode communicates directly with the kernel through some shared structs, which change depending on build options. There are sometimes extensive changes to both the microcode, kernel and userspace code depending on the revision of the SGX, customer project and build options, and sometimes the whole stack is affected, from microcode to userspace. This makes the powervr a very unstable platform: change one component, and the whole house of cards comes tumbling down. A nightmare for system integrators, but also bad news for people looking to provide a free driver for this platform. As if the murderous release cycle of mobile hardware wasn't bad enough of a moving target already.
The logic behind me attempting to keep people away from REing the PowerVR is, at one end, the attempt to focus the available decent developers on more rewarding GPUs and to keep people from burning out on something as shaky as the PowerVR. On the other hand, by getting everyone working on the other GPUs, we are slowly forcing the whole market open, singling out Imagination Technologies. At one point, IMG will be forced to either do this work itself, and/or to directly support open …